Padlocks can have shackles of lengths from ½-inch up to and including 6 inches. Padlocks with even longer shackles, up to almost 20 inches have been prepared. For the lower grades of locks, the locks made with the shackle permanently secured to the lock body it is not possible to change shackles. This requires the locksmith, or store, or manufacturer to carry a large inventory of locks having different shackles. More expensive locks have replacement shackles which normally require at least removal of the locking assembly from the lock to change the shackle. Some locks require removal of a pin from the back of the body to change a shackle.
Some locks are normally made either to retain the key in the lock when the lock is unlocked or open or to permit the key to be removed when the lock is unopened or locked state. Expensive locks can be converted from key retaining to key nonretaining by replacing either the key cylinder assembly or the key cylinder plug, or for some locks, replacing an adapter positioned between the key cylinder assembly and the lock ball retainer.
The present invention provides a cylinder plug which permits the lock to be made key retaining by the insertion of a pin at the driver end of the cylinder plug, or made non-key retaining, i.e. key nonretaining, by removal of a pin from the driver end of the cylinder plug. By key retaining, it is meant that the lock retains the key in the cylinder assembly when the lock is in the unlocked state. By key nonretaining, i.e. non-key retaining, it is meant that the key can be removed from the lock in the unlocked state. By the unlocked state, it is meant that both arms of the shackle are not secured within the lock body by the locking mechanism.